Key Lime Tart

Down in Key West on my annual boondoggle to cook for my cousins Rob and Ab and their merry band of sailors as they narrowly hang onto second place in their J-111 class, and their son, Ryan, skippers the 88, with his sister cousin Maegan aboard. And so, in honor of place, I’m posting this recipe from my book Egg: An Exploration of the World’s Most Versatile Ingredient: a key lime tart. It is indeed one of the finer desserts I know, custard made with yolks, topped with sweetened, whipped egg whites that are lightly browned.

It’s been a week of fun food, fish tacos (using beautiful yellow tail snapper), a lobster night which is always something of a celebratory meal (with leftover strip steaks), last night an easy protein for me, D’Artagnan’s most excellent duck confit, cheesy grits, a soft-egg cooked sous vide on the grits, sautéed zucchini, and salad. And tonight, the crowd pleasing paella, with local fish, un-local mussels, and sausages. Rain or no rain, goddammit. At least we’re not in the blizzard.

Preheat the oven to 350 degrees F./180 degrees C. Position a rack in the center of the oven.

To make the crust, combine the almond flour and all-purpose flour in a medium bowl. In a small bowl, light whip 2 of the egg whites with 3 tablespoons of sugar, whisk until sugar is dissolved. Add the egg white mixture and the melted butter to the flour mixture. Stir till it all comes together. Press the mixture into the bottom and up the sides of a 9-inch/23-centimeter tart pan.

Bake the crust till it looks appealingly golden brown, 10 to 12 minutes. Set as side to cool.

For the filling, whisk together all 5 egg yolks, the sweetened condensed milk, lime juice, and lime zest in a medium bowl. Pour the mixture into the cooled tart crust.

Bake until the center is set but still moves a bit when the pan is nudged, 20 to 30 minutes. Remove the tart from the oven and allow it to cool completely.

Before serving, make an Italian meringue with the remaining 3 egg whites (equal parts egg white and sugar by weight, cooking the sugar to 250 degrees F./120 degrees C.) Pipe or spread the meringue onto the cooled pie and broil the top to brown it lightly or hit it with a blowtorch for color. Slice and serve.

5 Comments

Allen
on January 23, 2016 at 10:13 am

My quest for the best key lime pie added toasted coconut, crushed peanuts to the outer portion of the whipped cream, exposed custard in the center with grated zest or candied lime slice.
Crust was always butter, sugar & graham crackers, but I found crushed almonds and a little coconut gave it a nice tropical crunch.
Of course I’m not cooking for mass people, I’m sure I would love them like all your other recipes, especially if it was in Key West during winter.
Hope to see pictures and post of your fabulous meal planning.
Cheers!

I absolutely LOVE Key West and key lime pie! And- seeing as I have 7 dozen eggs in my fridge (happy hens) I should make one to get my mind off the snow storm happening outside! Can you recommend a sugar free version or at least a substitute for the sugar in this recipe?

Thank you for NOT adding green food coloring and NOT burying it under whipped cream or (horror!) Cool Whip.

I can just see that your filling is a creamy yellow, as it should be.

egg yolks, sweetened condensed milk, and key lime juice. We folks here in Florida stir until the lime juice makes the protein strands in the eggs firm up — we don’t bother baking the filling (other than the time to brown the meringue if we even use the meringue), and salmonella be damned.

THE CRUST
Traditionally, Key lime pie is made with a near-effortless crust of graham cracker crumbs, sugar, and butter. Some of the recipes we tested added almonds to the equation. And one even threw a honey nut cereal into the mix. But though we liked the almonds (not so much the cereal), none of these crusts delivered the classic Key lime crust we were looking for. One addition we did accept? A little ground cinnamon, which we found in this pie crust. With a little extra butter to help it hold its shape and cut down on crumbliness, and a pinch of salt (because every crust needs a little), we were set.

THE CUSTARD
The custard base for the Key lime pie was the only element that divided our staff. This custard is traditionally three ingredients: eggs, lime juice, and sweetened condensed milk. Usually just egg yolks are used, which creates a smooth, glossy, almost gelatinous custard, preferred by some (like me). But other recipes call for whipping a few egg whites and folding them into the base, resulting in a lighter, fluffier texture. (And one recipe even used softened vanilla ice cream, resulting in a texture that resembles a semifreddo—a very un-Key Lime Pie-like consistency.) In an effort to control the amount of sweetness going into our pie, we tested a filling with evaporated milk plus our own prescribed amount of sugar. The outcome? Epic fail. It was a tan, grainy mess. Ultimately we couldn’t beat the classic egg yolk and sweetened condensed milk base, so we stuck with that.
THE CITRUS
Key limes are smaller and have a higher acidity (and a more tart, more bitter flavor) than regular limes. Our only complaint about the beloved Gourmet pie recipe was a hint of that characteristic bitterness—despite the saccharine quality of the condensed milk, that tannic Key lime flavor was still getting through. To get to the bottom of it, we baked pies using only Key lime juice, pies using bottled Key lime juice, and pies using a combination of half Key lime and half regular lime juice. The bottled Key lime juice was astringent, with an unattractive color—it didn’t impress at all. The Key lime/regular lime mix was good but not great; the flavor seemed watered down.

Suddenly, between bites of pie, we were struck by an epiphany: what about a splash of lemon juice? Could lemon be just what our lime pie needed?

We made an all-Key lime juice pie and added a few tablespoons of fresh lemon to the filling. And what do you know: The sweet, floral lemon flavor was the answer to our problem. It cut the bitterness of the Key limes in just the right way, without detracting from the delicate sweet-and-sour harmony we struck between the citrus juice and the sweet, rich custard.